Somatosensory Plasticity in Pediatric Cerebral Palsy following Constraint-Induced Movement Therapy.

Pawel J Matusz,Jennifer Pearson,Micah M Murray,Megan L Auld,Alexandra P Key,Shirley Gogliotti,Nathalie L Maitre

doi:10.1155/2018/1891978

Abstract

Cerebral palsy (CP) is predominantly a disorder of movement, with evidence of sensory-motor dysfunction. CIMT1 is a widely used treatment for hemiplegic CP. However, effects of CIMT on somatosensory processing remain unclear. To examine potential CIMT-induced changes in cortical tactile processing, we designed a prospective study, during which 10 children with hemiplegic CP (5 to 8 years old) underwent an intensive one-week-long nonremovable hard-constraint CIMT. Before and directly after the treatment, we recorded their cortical event-related potential (ERP) responses to calibrated light touch (versus a control stimulus) at the more and less affected hand. To provide insights into the core neurophysiological deficits in light touch processing in CP as well as into the plasticity of this function following CIMT, we analyzed the ERPs within an electrical neuroimaging framework. After CIMT, brain areas governing the more affected hand responded to touch in configurations similar to those activated by the hemisphere controlling the less affected hand before CIMT. This was in contrast to the affected hand where configurations resembled those of the more affected hand before CIMT. Furthermore, dysfunctional patterns of brain activity, identified using hierarchical ERP cluster analyses, appeared reduced after CIMT in proportion with changes in sensory-motor measures (grip or pinch movements). These novel results suggest recovery of functional sensory activation as one possible mechanism underlying the effectiveness of intensive constraint-based therapy on motor functions in the more affected upper extremity in CP. However, maladaptive effects on the less affected constrained extremity may also have occurred. Our findings also highlight the use of electrical neuroimaging as feasible methodology to measure changes in tactile function after treatment even in young children, as it does not require active participation.

Highlights

Cerebral palsy (CP) is a disorder of movement originating from perinatal insults to the developing brain, with an incidence of 2–3 children per 1000 in the developed world.While CP is predominantly characterized by neuro-motor abnormalities, recent research has demonstrated the essential role of somatosensory system dysfunction in impaired movement generation
An electrical neuroimaging approach to the analysis of event-related potential (ERP) can further leverage the spatio-temporal information in the ERP data to clarify if alterations in brain source configuration or strength of response of the same network contribute to motor function deficits and/or their recovery in pediatric CP
In a subsequent time period (~250–550 ms), only the ERP topography in response to stimulation of the more affected hand post-CIMT correlated with the reference condition, with spatial correlations involving the other conditions remaining near 0 (Figure 3(a)). These results suggest that ERPs to touch at the more affected hand post-CIMT intervention exhibited topographic distributions more similar to those in the ERPs of the less affected hand pre-CIMT intervention

Summary

Introduction

Cerebral palsy (CP) is a disorder of movement originating from perinatal insults to the developing brain, with an incidence of 2–3 children per 1000 in the developed world.While CP is predominantly characterized by neuro-motor abnormalities, recent research has demonstrated the essential role of somatosensory system dysfunction in impaired movement generation. An electrical neuroimaging approach to the analysis of ERPs can further leverage the spatio-temporal information in the ERP data to clarify if alterations in brain source configuration or strength of response of the same network contribute to motor function deficits and/or their recovery in pediatric CP. These mechanistic insights are afforded by robust, reference-independent, and global analyses of the electric field at the scalp (e.g., [10, 11]). Electrical neuroimaging analyses have been invaluable for identifying temporal and spatial mechanisms governing plasticity of sensory representations in both healthy (e.g., [12,13,14]) and developmentally atypical subjects [15, 16]

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